Subject: Abstract: sperm whales (fwd)

Michael Williamson (pita@whale.simmons.edu)
Wed, 10 Jul 1996 11:51:01 -0400 (EDT)

Subject: Abstract: sperm whales



Jaquet, N. and Whitehead, H. (1996). Scale-dependent correlation of
sperm whale distribution with environmental features and
productivity in the South Pacific. Marine Ecology Progress Series
135 : 1-9.


The purpose of this study was to investigate sperm whale (Physeter
macrocephalus) distribution in relation to underwater topography,
temperature gradients and primary and secondary productivity. The
influence of these factors over different spatial scales (80 - 640
nautical miles) was examined, and the importance of food resources
in determining sperm whale distribution was assessed .
The data were collected during a survey around the South Pacific.
Principal component analyses were used to assess the relationship
between the environmental measures recorded and to relate them to
sperm whale density. The first principal component was considered
as an index of secondary productivity, the second as an index of
underwater topography, and the third as a contrast between deep
and surface productivity. Sperm whale density was correlated with
the first and the second principal components over spatial scales
equal to or greater than 320 nautical miles. This result indicates that
sperm whales are generally distributed within large areas which are
characterized by high secondary productivity and steep underwater
topography. The size of these areas may reflect the distances over
which the groups of whales move in search of food. The absence of
correlation over smaller spatial scales suggests that factors other
than the distribution of food resources also influence sperm whale
distribution over these scales.

Nathalie Jaquet
Biology Dept., Dalhousie University, Halifax, NS, Canada
E-Mail: njaquet@is.dal.ca